The vertical form fill sealing (VFFS) machine is a type of automated assembly-line product packaging system. It is commonly used in the packaging industry for food and a wide variety of other products. The machine often constructs plastic bags out of a flat roll of plastic film, while simultaneously filling the bags with product and sealing the filled bags. Both solids and liquids can be bagged using this packaging system.
The typical machine is loaded with a continuous flat roll of plastic film, which has had labeling and artwork applied to the exterior or interior of the film. However, other types of material, such as paper, can also be used in a VFFS machine.
In a typical VFFS, the film approaches the back of a long hollow and preferably conical tube, which is called the forming tube. The outer edges of the film form flaps that wrap around the forming tube. The film is pulled downward around the outside of the tube and a vertical sealing arrangement forms a vertical seal. In case of a plastic film, the vertical sealing arrangement often comprises a heat-sealing bar that clamps onto the edges of the film to create the vertical/longitudinal seal by melting the seam edges together.
To start the bagging process in the typical VFFS machine, a horizontal sealing bar creates a “bottom seal” by clamping across the tube, bonding the film together and cutting off any film below. This sealing bar can be on a fixed height, which is called an intermittent sealing process. Faster systems include a sealing bar that moves down with the bag while sealing. This is sometimes referred to as a continuous process. The product can be pre-measured, e.g. by a multihead weighing system. Alternatively, the sealed tube end is lowered onto a precision weighing table and the product to be bagged is dispensed in the center of the bag. When the gross weight of the product-filled bag is reached, filling stops and the horizontal sealing bar seals the top of the bag and simultaneously forms the bottom of the next bag above. This bag is then cut off from the tube and is now a sealed package, ready to advance onward into product boxing and shipping processes.